Tailoring the C library to a new execution
environment

Tailoring the C library to a new execution environment involves
re-implementing functions to produce an application for a new execution
environment, for example, embedded in ROM or used with an RTOS.

Symbols that start with a single or double underscore name
functions that are used as part of the low-level implementation.
You can re-implement some of these functions. Additional information
on these library functions is available in the rt_heap.h, rt_locale.h, rt_misc.h,
and rt_sys.h include files and the rt_memory.s assembler
file.